How to cut sorbothane?

Interesting.

Common sense, and an undergraduate course in Building Construction tells me the following statement from the Herbie's website applies to any material, until that material reaches the failure point:

As weight load increases, the materials become increasingly resistant to compression.

Does anyone know of a material that becomes increasingly less resistant to compression as the weight load increases?

I'm going to try the 40 durometer sorbothane. If I hear no benefit, then I'll chalk it up to an experiment and move on.

BTW, McMaster-Carr carries a plethora of denser and less compliant materials than the various grades of sorbothane.

I think that I read in some reviews that whatever synthetic composite that Herbies uses is sonically better than Sorbothane. I could be wrong on that tho.

I did place Herbies footers under my cdp 2 days ago and am very happy with the result. Increased size of sound stage, better instrument separation while maintaining natural instrument timbre. The results were not subtle.

Good luck.

Sorbothane is a proprietary thermoset polyurethane formulation. They have a patent on the specific formulas, blend to the various durometers, and add modifiers for specific applications (chemical resistance, fire retardation, etc.). Several polyurethane blenders make similar products, Sorbothane is just marketed for vibration isolation and absorption applications.

Thermoset polyurethanes are an isocyanate and a polyol (resin and hardener) that are mixed together and allowed to set. They cannot be remelted, hence thermoset - not thermoplastic. Most specialty polyurethane manufacturers' have large drums of polyols, isocyanates, and the modifiers they use in their formulations, going from drum to drum by hand, creating the specific formulation of their products.

Within the same polyurethane product category, a change of durometer is often as simple as a change of one element in the hardener or mix ratio.

In other words, you wouldn't believe how simple it is to blend polyurethane compounds. We have several polyurethane mixes in our facility that produce the same "isolation effect". Sorbothane just found a modifier (probably a plasticizer) that they can sink their marketing teeth into, did the work to document the properties, and applied for a patent/s.

The point kinda is - each manufacturers' formulation will be slighty different (but patentable) leading to a very similar effect in material properties.

Sorry for answering a question that nobody really asked, but you happen to be talking about a subject I actually have a little knowledge in.(Now some bona-fide PhD Chemist/Audiophool is going to burn my noogies for opening my mouth and show me just how little I really know).

And yes, when I got around to it, I was going to put together isolation devices from the polyurethanes I work with and see if it works/helps.

Jim S.

Thanks, Jim. That was educational.

Grant- i think that your idea of just cutting some squares or rectangles is the best solution. The cost of the proper tool is only viable if you are making dozens of discs. let us know how it sounds.